Interdecadal modulation of El Nino amplitude during the past millennium
Interdecadal modulation of El Nino amplitude during the past millennium
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DOI：
10.1038/nclimate1086
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发表时间：
2011-05-01
影响因子：
30.7
通讯作者：
Zheng, Xiao-Tong
中科院分区：
文献类型：
--
作者：
Li, Jinbao;Xie, Shang-Ping;Zheng, Xiao-Tong
厄尔尼诺/南方涛动（ENSO）是地球上年际气候变率的主要模式，在热带太平洋以2-8年的间隔在异常温暖（厄尔尼诺）和寒冷（拉尼娜）条件之间交替（1，2）。ENSO变率的幅度影响着世界各地极端气候的发生和可预测性（3，4），但我们探测和预测ENSO变率变化的能力受到限制，因为仪器记录太短，无法表征其自然变率（5-8）。在这里，我们使用北美干旱地图集（9，10）--一个基于树木年轮记录的干旱重建数据库--来产生过去1,100年来ENSO变化的连续的、每年分辨的记录。我们的记录与太平洋及周边区域独立的、对厄尔尼诺/南方涛动敏感的代用记录大体一致。总之，这些记录表明，ENSO振幅呈现出50-90年的准规则周期，与热带太平洋平均状态密切相关。东太平洋异常温暖的条件与增强的ENSO变率有关，与模式模拟一致（11）。这里报告的准周期性厄尔尼诺/南方涛动振幅调制为改进模型及其对与全球变暖有关的厄尔尼诺/南方涛动行为的预测提供了一个关键的观测制约因素。
The El Nino/Southern Oscillation (ENSO) is the dominant mode of interannual climate variability on Earth, alternating between anomalously warm (El Nino) and cold (La Nina) conditions in the tropical Pacific at intervals of 2-8 years(1,2). The amplitude of ENSO variability affects the occurrence and predictability of climate extremes around the world(3,4), but our ability to detect and predict changes in ENSO amplitude is limited by the fact that the instrumental record is too short to characterize its natural variability(5-8). Here we use the North American Drought Atlas(9,10)-a database of drought reconstructions based on tree-ring records-to produce a continuous, annually resolved record of ENSO variability over the past 1,100 years. Our record is in broad agreement with independent, ENSO-sensitive proxy records in the Pacific and surrounding regions. Together, these records indicate that ENSO amplitude exhibits a quasi-regular cycle of 50-90 years that is closely coupled to the tropical Pacific mean state. Anomalously warm conditions in the eastern Pacific are associated with enhanced ENSO variability, consistent with model simulations(11). The quasi-periodic ENSO amplitude modulation reported here offers a key observational constraint for improving models and their prediction of ENSO behaviour linked to global warming.